Problem: What is the least common multiple of 20 and 30? Another way to say this is: $\lcm(20, 30) = {?}$
Solution: The least common multiple is the smallest number that is a multiple of 20 and 30. We know that 20 x 30 (or 600) is a common multiple, but is it the least common multiple? Write out the multiples of 30 until we find a number divisible by 20. 30, 60, So, 60 is the least common multiple of 20 and 30.